System and method for transmitting information between multiple objects moving at high rates of speed

ABSTRACT

Provided herein is a system for transmitting data to a motor vehicle travelling along a roadway. The motor vehicle preferably contains an antenna which produces a magnetic field having a length (L) in the direction of travel and a width (W) perpendicular to the direction of travel. A first plurality of RFID transponders may be positioned in the roadway as a row which is perpendicular to the direction of travel. A second plurality of RFID transponders may be positioned following the first row and offset from the first row. Depending on the speed of the vehicles travelling the roadway at this location, more rows of transponders may be used. A method for placing the RFID transponders within the roadway is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Application No. 61/603,032filed on Feb. 24, 2012 and is herein incorporated by reference in itsentirety.

TECHNICAL FIELD

Exemplary embodiments generally relate to the use of Radio FrequencyIdentification (RFID) as a means for transmitting information betweenmultiple objects moving past each other at high rates of speed.

BACKGROUND OF THE ART

The dangers of operating a motor vehicle at high speeds have been welldocumented by the high number of accidents causing both injuries andfatalities by operators, passengers, and sometimes even bystanders.Often times, the severity of the accident can be substantially reducedif the speed of the vehicles can be adequately controlled. It is nowdesirable to create an Adaptive Motor Vehicle Governing (AMVG) System toimprove the safety of roadways. The AMVG System may be used to regulatethe speed of motor vehicles to ensure compliance with established speedlimits. Direct control, easy installation and manageable maintenancemake the AMVG System an extremely viable solution to the growing problemof speed related accidents. Other embodiments of the AMVG System allowthe transmission of other types of information to a motor vehicle movingat a high rate of speed.

The use of RFID as an enabling technology effectively addresses theissue of direct control. RFID is an automatic identification method andrelies on storing and remotely retrieving data using a device called anRFID tag or transponder, which is a small object that can be attachedto, or incorporated into, an object. RFID transponders contain siliconchips and antennas that enable them to receive and respond toradio-frequency queries from an RFID reader. Identification is performedalmost instantly (within milliseconds). Additionally, identificationdoes not require contact or a direct line of sight. Similarly, passiveRFID transponders require no internal power source and run off ofinduction, whereas active RFID transponders require a power source. TheRFID transponders store unique information and serve as a portable datacarrier.

Generally, the process begins when a passive battery-less RFIDtransponder is charged through induction from the RFID antenna'smagnetic field. The RFID antenna is the part of the system that radiatesthe induced magnetic field energy to, and receives information from, theRFID transponder. A magnetic field is generated by the RFID reader'sRFID antenna and charges a capacitor in the RFID transponder. The RFIDreader cycles between creating a magnetic field to charge an RFIDtransponder through induction and listening for a radio signal back fromthe RFID transponder. This cycle is continuous and allows the RFIDreader to communicate with RFID transponders placed within the RFIDantenna's read range without being queued. Once the RFID transponderstops receiving power through induction and its capacitor is fullycharged, it sends its programmed information to the RFID reader. Thisinformation is deciphered by the RFID reader and documented according toa specified application.

Others have proposed using road-side RFID transponders with RFID readerslocated in each vehicle. There are several problems with thisimplementation. There are three frequency ranges used for RFID; UltraHigh Frequency (UHF), High Frequency (HF) and Low Frequency (LF). Radiosignals are electromagnetic waves and have a magnetic component and anelectric component. LF and HF systems use the magnetic field to transferpower by induction. This field has a well-defined zone, but the strengthof the field falls off quickly. UHF systems use the electric field totransfer power by capacitive coupling. The strength of this field doesnot fall off as quickly, so potentially longer read distances arepossible. Reflection means that the zone is less well defined. As aresult, UHF has the potential for the largest read range but has theleast potential to penetrate through materials. Conversely, LF has thepotential for the smallest read range but has the greatest potential topenetrate through materials. HF falls in the middle of these twoextremes. Thus, on a multi-lane highway, a road-side reader would havedifficulty reaching vehicles in the middle or opposing lanes.

Further, the presence of metal can present a variety of interferenceissues with RFID systems. Obviously, the primary material used toconstruct vehicles is metal, and there is a large presence of this onpublic roadways. Water, in its various phases, can also posetransmission issues with UHF and HF RFID systems. Thus, signals caneasily be disrupted during rain, snow, or hail as well.

These factors, combined with the high speed of travel along manyroadways, present several unsolved issues for an RFID speed controlsystem. The embodiments of the AMVG System described herein provide anumber of new advantages. The embodiments herein provide a high poweredRFID antenna attached to an object, to ensure accurate transmission ofauthenticated information to an RFID reader, without interference fromother active RFID devices within close proximity, when an RFIDreader/RFID antenna pass in close proximity of RFID transponder(s) athigh rates of speed. In this exemplary embodiment LF RFID is preferred.

SUMMARY OF THE EXEMPLARY EMBODIMENTS

The Roadway Network should consist of RFID transponders called RoadwayNetwork Transponders (RNTs) programmed with the speed limit of thecorresponding roadway. These RNTs will be placed in the roadway in amanner that allows for accurate performance based on the requirementsand limitations of RFID technology, enabling the AMVG System.

The In-car Device preferably consists of an RFID antenna, placed inelectrical communication with an RFID reader and an electronic/computercontrolled Motor Vehicle Throttle Control System (MVTCS). The RFIDantenna is the device that creates the magnetic field required for theinduction powered RNTs to transmit the encrypted coded information/datato the RFID reader, which occurs via radio waves. The RFID antenna ispreferably positioned along the bottom perimeter of the motor vehicle toensure proper read distance in relation to the RNTs. The RFID antenna isconnected to the RFID reader, which initiates the transmission ofinformation through the RFID antenna from the RNTs. The RFID reader isalso the device that decodes the radio wave transmitted information/datacoded on the RNTs. This information (i.e., the speed limit of theroadway) is then communicated to the computer controlled MVTCS, which isthe device that ultimately controls/governs the motor vehicle's speed.Motor vehicle manufacturers change their production processes on ayearly basis. Vehicle features are added and improved and productionmethods are changed frequently. This will allow for a safety device suchas the AMVG System to be implemented easily into existing manufacturingsystems. A coordinated effort between each individual motor vehiclemanufacturer and a qualified AMVG System design team will design allspecific components required for each type/style of motor vehicle,procure all necessary materials, design all manufacturing requirementsand execute implementation of the AMVG System in all motor vehicles soldto operate on U.S. public roadways.

The maintenance of the RNTs should be extremely manageable due tolongevity, durability and encryption safety features. Pursuant to theoriginal installation plan, a program may be in place to ensure timelyinstallation of RNT replacements. All the required entities, assets,installation specifications and personnel may be established and willcontinually monitor the system's performance to complete all maintenanceneeds. RNTs may be damaged, speed limits will change and new roads willbe built; therefore, a maintenance program that inspects the RNTs on acontinual biennial basis is sufficient to address any ongoingconstruction and troubleshooting issues that may arise. Specialinspection motor vehicles can be equipped with RNT software installationequipment and speed limit validation recording tools and will enablemaintenance crews to efficiently maintain a safe and secure AMVG Systemoperation. Other government vehicles, such as police vehicles, may alsohave the RNT performance tracking systems installed and may documentlocations of failed RNTs. This information can then be forwarded tolocal Departments of Transportation so maintenance can be efficientlycompleted. The encryption safety features will prevent any issues ofpublic delinquency by allowing the RFID reader to authenticate theinformation received from the RNT.

The foregoing and other features and advantages will be apparent fromthe following more detailed description of the particular embodiments ofthe invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of an exemplary embodiment will be obtained froma reading of the following detailed description and the accompanyingdrawings wherein identical reference characters refer to identical partsand in which:

FIG. 1 provides a general schematic layout for Speed LimitIdentification Zones (SLIZs) and an RFID antenna magnetic field.

FIGS. 2-11 provide a schematic layout for several examples of thelocation of the Speed Limit Identification Zones (SLIZs).

FIGS. 12-29 provide a schematic of several examples for the location ofthe SLIZs.

FIGS. 30-34 show schematics for several embodiments of locations of theSLIZs.

FIG. 35 provides a sectional view of an exemplary embodiment forinstalling the various RNTs within a roadway.

FIG. 36 provides an electrical schematic of one embodiment for the motorvehicle components including the MVTCS.

FIG. 37 provides an electrical schematic of one embodiment for theInformation Communication Network System.

DETAILED DESCRIPTION

The invention is described more fully herein after with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe scope of the invention to those skilled in the art. In the drawings,the size and relative sizes of layers and regions may be exaggerated forclarity.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layers.In contrast, when an element is referred to as being “directly on”another element or layer, there are no intervening elements or layerspresent. Like numbers refer to like elements throughout. As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

It will be understood that, although the terms first, second, third,etc., may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare used only to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention.

Spatially relative terms, such as “lower”, “upper” and the like, may beused herein for ease of description to describe the relationship of oneelement or feature to another element(s) or feature(s) as illustrated inthe figures. It will be understood that the spatially relative terms areintended to encompass different orientations of the device in use oroperation, in addition to the orientation depicted in the figures. Forexample, if the device in the figures is turned over, elements describedas “lower” relative to other elements or features would then be oriented“upper” relative the other elements or features. Thus, the exemplaryterm “lower” can encompass both an orientation of above and below. Thedevice may be otherwise oriented (rotated 90 degrees or at otherorientations) and the spatially relative descriptors used hereininterpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Embodiments of the invention are described herein with reference tocross-section illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures) of the invention. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, embodiments of the invention should not be construed aslimited to the particular shapes of regions illustrated herein but areto include deviations in shapes that result, for example, frommanufacturing.

For example, an implanted region illustrated as a rectangle will,typically, have rounded or curved features and/or a gradient of implantconcentration at its edges rather than a binary change from implanted tonon-implanted region. Likewise, a buried region formed by implantationmay result in some implantation in the region between the buried regionand the surface through which the implantation takes place. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to illustrate the actual shape of a region of adevice and are not intended to limit the scope of the invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

It is preferable that the speed limit data stored on the RNTs beencrypted to increase security and prevent public delinquency. Theformat of the information transmitted from the RNTs should beidentifiable as authentic to avoid the AMVG System from being used in adelinquent manner. To ensure the authenticity of informationtransmission, an algebraic code may be created using the 16-character,eight position data storage format or 64 bit memory available on a LowFrequency 120 mm RFID transponder to secure the system's operation.

Read only RFID transponders may be used to prevent delinquent avoidanceof the AMVG Systems control. It may be preferable to isolate anypotential delinquent avoidance or manipulation of the system and as aresult read only RFID transponders should be used for the system toperform properly.

This application of RFID technology is new and has design constraintswhich may test the limits of this technology. Although not required,using 120 mm transponders will satisfy the read distance constraintsrequired for the AMVG System to operate. The RFID antenna examples shownbelow have been designed to ensure the size and strength necessary tocharge and receive information from the RNTs at the speeds to which thisdevice will be applied, however many designs of possible antennas wouldwork with the exemplary embodiments herein. Additionally, RNTs may beoriented in a manner that allows for the fastest charge rate.

Low frequency RFID transponders are passive and require no battery orpower source to operate. These RFID transponders use induction to chargea small capacitor within. This capacitor holds the required charge andreleases it to transmit the data contents stored on the RFID transponderthrough the RFID antenna to the RFID reader. Induction passes a chargebetween two coils of wire through the air and this process requires thecoils between which the charge is transmitted to be aligned with themagnetic field generated. As a result, the RFID transponder should beoriented like a bullet entering a target for the most efficientoperation.

It is preferable to have SLIZs in each location at which the speed limitchanges or an access point (on ramps and intersections) is passed on aroadway with a speed limit greater than or equal to 50 mph. It is alsopreferable to have multiple SLIZs on an AMVG System controlled highwayeven if the speed limit does not change or an access point is passed.This may provide added security. Repetitive transmission of informationallows for more accuracy and prevention of public delinquency in thesystem's operation. It also allows the speed governing In-car Device totime out and stop controlling the speed of an AMVG System controlledmotor vehicle after a specified distance of travel. This will ensure anAMVG System controlled motor vehicle can operate at any speed, whetherlegal or not, on a U.S. public roadway not controlled by the AMVG Systemor on private property.

RNTs are preferably placed frequently enough to allow for correctoperation of the AMVG System. Since the RNTs are to be read by a motorvehicle moving at speeds sometimes in excess of 70 mph, repetitive,identically programmed transponders are preferred. This will allow formore accurate reading of the data stored on the transponders (the speedlimit of the U.S. public roadway being traveled). The layout oftransponders should preferably cause all passing motor vehicles to passwithin the read range of 1 to 5 RNTs, preferably guaranteeing twoauthentic signal transmissions occur when passing over a SLIZ.

Research regarding how LF RFID technology reacts and functions whencommunicating information between objects moving at speeds greater than50 mph is not readily available to the public. The technology'sspecifications, however, suggest there are no limitations with respectto the rate of speed at which the RFID antenna magnetic field and RFIDtransponder can pass and still transmit information, as long as the RFIDsystem is designed properly. The most important factor affecting theinformation transmission speed is the amount of time an RFID transponderis within the RFID antenna's charge and signal transmissions range. Thecurrent off-the-shelf RFID reader constraints allow a minimum magneticfield pulse/RFID transponder charge duration of 15 ms and minimum radiosignal observation/RFID transponder signal transmission duration of 20ms. These factors define RFID transponder charge/read cycle to be 35 ms.Therefore, the higher rate of speed at which the RFID antenna magneticfield and RFID transponder pass, the larger the RFID antenna magneticfield must be in order to ensure the RFID transponder is within the RFIDantenna's charge/signal transmission range to ensure two full RFIDtransponder charge/read cycles occur.

RFID signal transmission is typically subject to electromagnetic noiseinterference. As a result, the industry standard is to require two ormore signal transmissions to ensure authentic information iscommunicated.

A simulation of the physical components for one possible design of theAMVG System has been created and provides valuable insight. Computersimulations provide the capability to model a physical activity usingstatistically based parameters and execute the activity many times in ashort period of time to determine how it will perform. The followingsection sets forth an explanation and results of an example of acomputer simulation model used for the exemplary embodiments of the AMVGSystem.

The computer simulation model utilizes two entities: one represents thevehicle traveling over the RFID transponders and the other representsthe signal emitted from the RFID antenna in the vehicle. There is auniform distance between each of the RFID transponders and the vehicletravels at a constant speed while passing over the RFID transponders.

The model begins by creating both entities at the same time with arandom start time between 0 and 35 ms. This random start time is used torepresent the varying charge/read cycle random start times resultingfrom a vehicle initiating the RFID communication charge/read cycle time.This cycle affects when information is transmitted and, as a result,determines whether or not information can be transmitted via RFIDtechnology. A full 15 ms magnetic field pulse/RFID transponder chargeduration and consecutive 20 ms radio signal observation/RFID transpondersignal transmission is typically required, while the RFID transponder iswithin the RFID antenna's charge/signal transmission range, for RFIDtechnology to transmit information. If the RFID antenna, or moreimportantly, its magnetic field/listening range is not sufficient, RFIDtechnology cannot transmit information.

The vehicle entity first receives an individual ID to track the entityand then is delayed a calculated time determined by the speed of thevehicle and the distance between the RNTs before it reaches the firstRNT to ensure the signal entity has started. The vehicle is thenpreferably delayed for the time that the vehicle is over the RNT. Thisis a function of speed and RFID antenna magnetic field length. Duringthis delay, the vehicle is waiting for the signals (See Signal Deliverybelow).

If both signals are received in correct order, the remainder of thedelay may be postponed to ensure that the entire length of the vehicletravels over the RNT. Next, the vehicle is preferably delayed for theremainder of the distance between RNTs and then proceeds to the nextRNT. This process in this embodiment is repeated five times andrepresents the maximum number of RFID transponders (RNTs) that a motorvehicle could cross in actual system operation.

Using the simulation to represent a motor vehicle crossing 5 RNTs forevery individual simulation provides the statistical informationnecessary to determine how many RNTs must be passed at a given speed toensure at least two signal transmissions occur (the required amount ofsignal transmissions to ensure authentic repetitive information iscommunicated).

If both signals are not received in correct order, there is no need todelay the rest of the distance because the vehicle has traveled thelength of the RFID antenna magnetic field over the RFID Transponder anddid not receive a signal. Next, the vehicle may be delayed for theremainder of the distance between RNTs and then proceeds to the nextRNT. This process may then be repeated for each assigned RNT.

Signal Delivery—In order to ensure that the data from the RNT isreceived, the entire charge and read cycle should be accounted for,including precedent of order. To express this logically, two signals aresent: the first indicates the start of the charge cycle 15 ms and thesecond indicates the end of the discharge cycle 20 ms. The signalsshould be received in the order of charge signal, then discharge signalin order for the data from the RNT to be received.

The statistically modeled performance evaluation describes the actualoperating constraints defined by the physical limitations of themultiple components configured in a manner not previously evaluated andcomprised in the AMVG System. The results are shown in Table 1 below.The parameters of the AMVG Systems specifications modeled in thesimulation are as follows:

RFID reader charge time—15 ms

RFID reader read time—20 ms

RFID reader charge/read cycle time—35 ms

RFID reader charge/read cycle time randomizer—0 ms to 35 ms

RFID antenna magnetic field length—7.5 ft

RNT SLIZ quantity—5 RFID transponders

RNT spacing—8 ft

TABLE 1 Exact MPH (using Linear Interpolation) Receive 2 out of 5 RNTswith 100% Accuracy 93.27 Receive 2 out of 4 RNTs with 100% Accuracy89.09 Receive 2 out of 3 RNTs with 100% Accuracy 75.85 Receive 2 out of2 RNTs with 100% Accuracy 58.06 Receive 2 out of 1 RNTs with 100%Accuracy 30.40

The table above shows that if speeds of a motor vehicle traveling on aU.S. public roadway is less than or equal to 93 mph, 5 RNTs arerequired; less than or equal to 89 mph, 4 RNTs are required; less thanor equal to 75 mph, 3 RNTs are required; less than or equal to 58 mph, 2RNTs are required; and less than or equal to 30 mph, 1 RNT is requiredto ensure that 2 RFID signal transmissions occur. Speeds over 70 mph arenot typically controlled or legal, but there are situations in which amotor vehicle could accelerate above a speed where RFID signaltransmission can occur. Therefore, identifying and understanding theselimitations will determine the placement and quantity of RNTs requiredto ensure complete speed control.

Regarding transponders, two types may be used in various embodiments ofthe invention. First, read only passive RFID transponders may be used(ex. Texas Instruments Part Number: RI-TRP-R9TD or similar). Second,read/write active RFID transponders may be used (ex. Texas InstrumentsPart Number: RI-TRP-D9TD). The specifications for these can be found atwww.ti-rfid.com and are herein incorporated by reference as though fullyrecited herein.

Each type of transponder may be used in a number of differentsituations. Passive RFID Transponders may be used as Activation RNTs:roadway speed limit control (ex. 0 mph-93 mph preferably as defined bythe simulation), multiple point roadway speed limit control for vehiclesrequired to operate at different speed limits than general traffic (ex.0 mph-93 mph preferably as defined by the simulation), in one exemplaryembodiment preferably with a distance of speed limit control for 6,000ft, but can be any specified distance or no distance at all. PassiveRFID Transponders may also be used as Deactivation RNTs. Speed GovernorControl Removal: Deactivation RNTs may clear the current motor vehiclesspeed limit control, but can further limit the motor vehicles speed to93 mph for preferably 160 ft, but can be any specified distance or nodistance at all, in order to enhance the performance of the AMVG Systemthereby requiring fewer RNTs to be installed, while still ensuring thespeed limit information is properly communicated to a motor vehicleoperating on an AMVG System controlled U.S. public roadway.

Passive RFID Transponders may also be used as Utility RNTs for roadwaysafety information (ex. stop signs, yield signs, merge signs, or roadwayname signs) and/or public information signs (ex. airports, restaurant,retail stores, gas station, parks and tourist attractions).

Passive RFID Transponders may also be used as Temporary RNTs,temporarily controlling the speed limit of a roadway in an isolated area(ex. Construction zones, festival/marathon/public events, and othertemporary safety zones).

Active RFID transponders may be used as Dynamic RNTs. Because ActiveRNTs are not passive like Activation, Deactivation, Utility andTemporary RNTs, they do not receive their power to transmit informationvia the magnetic field created by the RFID antenna and RFID readerattached to an AMVG System equipped motor vehicle. Dynamic RNTs may bewired to a power source and will be connected to a computer network,which may be updated in real time to provide motorist information vitalto their safety, well-being, roadway traffic information and marketinginformation, among others.

Layout

The relative placement of each type of RNT will now be discussed. Asmentioned above, there can be at least five types of RNTs: ActivationRNTs, Deactivation RNTs, Utility RNTs, Temporary RNTs and Dynamic RNTs.SLIZs will include approximately 3-50 RNTs per lane of traffic,determined by the lane's width, the speed limit and maximum attainablespeed of the U.S. public roadway being controlled by the AMVG System andplaced in a staggered manner. The layout of RNTs in a SLIZ is designedto be independent of the roadway size and/or number of lanes,generalizing the specifications for all installation applications. As aresult, the installation of the RNTs will start on one side of theroadway and proceed as identified below, until reaching the other edgeof an AMVG System controlled U.S. public roadway pavement surface. Thisdesign assures that at any position on an AMVG System controlledroadway, a motor vehicle cannot pass a SLIZ without crossing therequired number of RNTs that assure the speed limit of the roadway isproperly communicated to passing motor vehicles and therefore the speedlimit of a motor vehicle is controlled.

FIG. 1 shows roadway 170 with SLIZ 180 comprised of an Activation Zonecontaining Activation RNTs 30 and a Deactivation Zone containingDeactivation RNTs 40. The Activation RNTs 30 and Deactivation RNTs 40are oriented with spacing A perpendicular to the flow of traffic,oriented with spacing D parallel to the flow of traffic and offset withspacing O perpendicular to the flow of traffic. Also shown here is amotor vehicle 160 having an antenna 50 that generates a magnetic fieldmeasuring L in a direction parallel to the traffic flow and W in thedirection perpendicular to the traffic flow. As noted above and below,antennas can be produced in a wide variety of styles and physicaldimensions, so for the purpose of simplicity here the exemplaryembodiments of the invention have been described in view of the magneticfield dimensions L and W, as many different types of antennas would workwith the exemplary embodiments herein.

In one example the first row of RNTs should preferably be positionedstarting at some offset (ex. 2.5 ft) off the edge of the pavementsurface (this placement maybe within the paved berm of the roadway). Thesecond RNT should preferably be positioned at distance A (ex. 5 ft) fromthe first RNT in the direction away from the edge of the pavementsurface where the SLIZ installation began. Both RNTs should preferablybe positioned in a line perpendicular to the flow of traffic. Thispattern should preferably continue all the way across the roadway, withapproximately distance A spacing, with the last RNT installed near theedge of the pavement surface opposite of where the SLIZ installationbegan.

The next row of RNTs should preferably be positioned at distance D (ex.8 ft) forward in the direction of the flow of traffic in the lane wherethe installation began and installed parallel to the first row of RNTs,starting at a larger offset (ex. 5 ft) from the edge of the pavementsurface where the SLIZ installation began (this placement may be withinthe paved berm of the roadway). The second RNT should preferably bepositioned at distance A (ex. 5 ft) from the first RNT in a directionaway from the edge of the pavement surface where the SLIZ installationbegan. Both RNTs should preferably be positioned in a line parallel tothe first row of RNTs installed. This pattern will continue all the wayacross the roadway, with approximate distance A spacing, with the lastRNT installed near the edge of the pavement surface opposite of wherethe SLIZ installation began.

The design specification for the installation of RNTs for the first andsecond rows of a SLIZ is preferably repeated in the same alternatingsequence as identified by the speed limit of the roadway beingcontrolled and outlined in the frequency section below.

Frequency

Roadway Network SLIZs may be located at least in the following locationson U.S. public roadways controlled by the AMVG System. There aretypically two categories of roadways: freeway U.S. public roadways andarterials/collectors/local U.S. public roadways. A freeway U.S. publicroadway is generally categorized as a road that has no traffic lights orrequired stopping points (excluding toll ways/mandatory personnel orvehicle inspections). These roads generally have no intersections andare accessed using on ramps and exited using off ramps.Arterials/collectors/local U.S. public roadways contain intersections,traffic signs, traffic lights and required stopping points.

The ingress to an exemplary AMVG System controlled roadway will now bediscussed. These AMVG System design constraints may be calculated usingthe statistical data determined by the simulation model presented inTable 1 above. The specifications may consist of two components. Thecomponent applied to a specific situation is determined by theapplication that maximizes the AMVG System's performance and minimizesthe quantity of RNTs required to be installed. SLIZs may be located onroadways not controlled by the AMVG System. These installations mayoccur when the roadway being controlled does not provide a location thatmeets the required specification necessary to properly control the speedof a motor vehicle operating on an AMVG System controlled U.S. publicroadway. The two components of the specifications are as follows: (1)RNTs are placed at a specified distance from the last required stoppingpoint on an AMVG System controlled U.S. public roadway; (2) RNTs areplaced on a radius or at a specified distance from the apex of a radius,where a motor vehicles speed is restricted by non-linear travel of themotor vehicle, on an AMVG System controlled U.S. public roadway.

The first component of the specification is placement of RNTs at aspecified distance from the last required stopping point on an AMVGSystem controlled U.S. public roadway. For example, using theinformation in the table above, a distance at which the fastest currentstreet legal motor vehicle (ex. Maxximus G-Force 0-60 mph in 2.134 s)can reach the speed at which 2 signals are received out of 5 RNTs, 2signals are received out of 4 RNTs, 2 signals are received out of 3RNTs, 2 signals are received out of 2 RNTs, 2 signals are received outof 1 RNT. These distances are determined by calculating the time periodat which the fastest current street legal motor vehicle can reach thespeeds identified in the table above 93.27 mph, 89.09 mph, 75.85 mph,58.06 mph and 30.40 mph using the equation below.

v ^(o) =initial velocity

v^(f)=final velocity

a=acceleration

t=time

d=distance

a=(v^(f)−v ^(o) )/t

t=(v^(f)−v ^(o) )/a

d=½ (v^(f)+v ^(o) )t

In the case of a motor vehicle that is capable of accelerating from 0-60mph in less time than 2.134 s, it requires a specially designed RFIDantenna with increased magnetic field strength and an RFID reader with areduced charge/read time mathematically calculated lower than thestandard design time period of 35 ms, which will allow the SLIZ designto properly control the speed of the vehicle. RNTs will preferably beinstalled across the entire roadway, including both directions oftraffic flow, unless there is a barrier between the lanes of differentdirections of traffic flow, to prevent delinquent avoidance of the AMVGSystems control. Table 2 shown below outlines the maximum attainablespeed ranges and associated distance ranges from the last requiredstopping point necessary to properly control the speed of a motorvehicle operating on an AMVG System controlled U.S. public roadway.

TABLE 2 SLIZ Distance From Transmission Speed Number of Last Required(mph) RNT's Stopping Point (ft) 00.00 > 30.40 1 0.00-8.00 30.41 > 58.062  9.00-55.00 58.07 > 75.85 3  56.00-102.00 75.86 > 89.09 4102.00-143.00 89.10 > 93.27 5 144.00-147.00

FIGS. 2-11 provide a schematic layout for several examples of thelocation of these SLIZs. These figures represent examples of eachspecification outline in the table above but do not show every possibleembodiment. All RNT quantities, distances from the last requiredstopping point, maximum attainable speeds, number of lanes, lane widthsand pavement surface size can be interchanged to apply to all potentialroadway applications.

The second component of the specification is the placement of RNTs on aradius or specified distance from the apex of a radius, where non-lineartravel restricts the speed of the motor vehicle traveling on an AMVGSystem controlled U.S. public roadway. In order to determine where toplace RNTs on a radius, the maximum radius dimensions to restrict thespeed to 93.27 mph at which 2 signals are received out of 5 RNTs, 89.09mph at which 2 signals are received out of 4 RNTs, 75.85 mph at which 2signals are received out of 3 RNTs, 58.06 mph at which 2 signals arereceived out of 2 RNTs, 30.40 mph at which 2 signals are received out of1 RNT may be determined.

In order to determine where to place RNTs at a distance from the apex ofa radius, the maximum radius dimensions to restrict the speed to 75.05mph, 74.04 mph, 62.57 mph, 40.30 mph, 17.63 mph should preferably bedetermined. The foregoing speeds are lower than the speeds used tocalculate RNT placements on radiuses because the linear travel/increasedpotential speed possible when RNTs are placed on a linear section ofroadway after a radius.

Below are the equations used to determine the maximum radius size anddistance from the apex of a radius that RNTs must be placed in order forthe speed limit of the road to be communicated to a passing motorvehicle.

r=radius

v=velocity

g=gravity

μ=coefficient of friction

θ=bank angle

r=(v²/g)(1-μ tan θ/tan θ+μ)

v ^(o) =initial velocity

v^(f)=final velocity

a=acceleration

t=time

d=distance

t=(v^(f)−v ^(o) )/a

d=½ (v^(f)+v ^(o) )t

Using 0.75 as the coefficient of friction provides a conservativespecification, assuring accuracy and performance of the AMVG System. Thefollowing calculations are determined from the equation above and allowfor a maximum bank angle of θ=8% or 4.57°. These design specificationsare used as an example but only represent the AMVG System designspecifications for this specific example. The equations above may beadjusted for other design specifications and extrapolated based on theprocedures outlined below to determine the AMVG System's specificationsfor each application.

Table 3 below outlines the maximum attainable speed ranges andassociated roadway radius sizes where RNTs are placed on the roadwayradius. These locations may be utilized to maximize the performance ofthe AMVG System operation limits by restriction of the speed of a motorvehicle as a result of non-linear travel and required to properlycontrol the speed of a motor vehicle operating on an AMVG Systemcontrolled U.S. public roadway.

TABLE 3 Transmission Number SLIZ Speed (mph) of RNT's Radius (ft)00.00 > 30.40 1 69.00 30.41 > 58.06 2 254.00 58.07 > 75.85 3 434.0075.86 > 89.09 4 599.00 89.10 > 93.27 5 657.00

Table 4 below outlines the maximum attainable speed ranges andassociated distance ranges, where RNTs are placed at specified distancesfrom the apex of a roadway radius. These locations may be utilized tomaximize the performance of the AMVG System operation limits byrestriction of the speed of a motor vehicle as a result of non-lineartravel and properly control the speed of a motor vehicle operating on anAMVG System controlled U.S. public roadway.

TABLE 4 SLIZ Location From SLIZ Location From SLIZ Location From SLIZLocation From SLIZ Location From Transmission Number of Tangent ofRadius Tangent of Radius Tangent of Radius Tangent of Radius Tangent ofRadius Speed (mph) RNT's 0′ > 23′ (ft) 24′ > 161′ (ft) 162′ > 295′ (ft)296′ > 414′ (ft) 415′ > 425′ (ft) 00.00 > 30.40 1 0 — — — — 30.41 >58.06 2  1.00-63.00 0 — — — 58.07 > 75.85 3  64.00-126.00 1.00-61.00 0 —— 75.86 > 89.09 4 127.00-183.00 62.00-118.00  1.00-56.00 0 — 89.10 >93.27 5 184.00-201.00 119.00-138.00  57.00-76.00 1.00-20.00 0

SLIZs may be placed on the radius or at the apex of the radius, with theradius measured of the fastest travelable route. FIGS. 12-29 provide aschematic of several examples for the location of these SLIZs. Thesefigures represent examples of each specification outlined in the tableabove but do not show every specified design application. All RNTquantities, radius sizes, distances from the apex of radiuses, maximumattainable speeds, number of lanes, lane widths and pavement surfacesizes can be interchanged to apply to all potential roadwayapplications.

In an exemplary embodiment of an AMVG System controlled U.S. publicroadway, SLIZs may be located at a distance up to the programmeddistance of speed limit control of Activation RNTs, but shouldpreferably be located every 5,500-5,660 ft from the SLIZ that could bethe immediately preceding SLIZ and is the farthest away (SLIZ locationscould be based from an on ramp, an intersection, the other direction oftraffic flow with access to a new control zone via a U turn or lastStandard Control Zone), with the required number of RNTs crossed setforth in Table 5 below. The layouts of the SLIZs are similar to thedesigns identified in FIGS. 2-11.

TABLE 5 U.S. Public Roadway Activation Speed limit (mph) RNT's 5 1 10 115 1 20 1 25 1 30 1 35 2 40 2 45 2 50 2 55 2 60 3 65 3 70 3 75 4 80 4 854 90 4 93 5

The following describes an exemplary embodiment for the egress of anAMVG System controlled freeway or arterial/collector/local U.S. publicroadway. There are typically two different specifications for theplacements of SLIZs when exiting an AMVG System controlled U.S. publicroadway.

The first specification for installing Deactivation RNTs is on an AMVGSystem controlled freeway or arterial/collector/local U.S. publicroadway based upon the speed limit of the road and may be located at adistance up to the programmed distance of speed limit control ofActivation RNTs, but preferably 0-80 ft back from anintersection/traffic light/traffic sign/required stopping point or endof an AMVG System controlled U.S. public roadway, on a U.S. publicroadway not intersecting with another AMVG System controlled U.S. publicroadway. The layouts of the SLIZs for a Deactivation Zone aresubstantially similar to FIGS. 2-6 shown above, except the RNTs will beDeactivation RNTs and programmed to preferably deactivate the AMVGSystem's control of a motor vehicles speed to 93 mph for 160 ft and thenpreferably no control after 160 ft. RNTs may preferably be installedacross the entire roadway including both directions of traffic flow,unless there is a barrier between the lanes of different directions oftraffic flow, to prevent delinquent avoidance of the AMVG System'scontrol. The Deactivation RNT SLIZ quantities are set forth in Table 6below. FIGS. 30-34 show schematics for several embodiments of locationsof these SLIZs.

The second specification for installing Deactivation RNTs is on an AMVGSystem controlled freeway or arterial/collector/local U.S. publicroadway intersecting an AMVG System controlled U.S. public roadway.Deactivation RNTs will preferably be placed in accordance with theingress specifications outlined above. RNTs will be preferably installedacross the entire roadway, including both directions of traffic flow,unless there is a barrier between the lanes of different directions oftraffic flow, to prevent delinquent avoidance of the AMVG Systemscontrol. The Deactivation RNT SLIZ quantities are identified in Table 6below. Some examples for the locations of these SLIZs are shown in FIGS.7-11, 22, 23 and 26-29. The figures represent examples of eachspecification outlined in the table below, but do not show every designapplication. All RNT quantities, radius size, distances from the apex ofa radius, maximum attainable speeds, number of lanes and pavementsurface size can be interchanged to apply to all potential roadwayapplications.

TABLE 6 U.S. Public Roadway Deactivation Speed limit (mph) RNT's 5 1 101 15 1 20 1 25 1 30 1 35 2 40 2 45 2 50 2 55 2 60 3 65 3 70 3 75 4 80 485 4 90 4 93 5

FIG. 35 provides a sectional view of an exemplary embodiment forinstalling the various RNTs within a roadway. Preferably, a hole isdrilled that is slightly larger than the diameter of the RNT and filledwith adhesive. Once inserted, preferably the RNT should sit flush or nomore than 0.25 in below the pavement surface. The pavement cut shouldpreferably be dry and free of dust, dirt, oil, grease or otherimpurities that could affect the bond of the adhesive with the RNT andthe surrounding pavement. Adhesive that is not flush with the pavementsurface should preferably be removed. RNTs should be placed when thepavement surface temperature and the ambient air temperature are atleast 40° F. (5° C.) and the pavement is dry. It may be preferred toheat both parts of the RNT adhesive to 100±10° F. (38±5° C.) duringinstallation when either the pavement surface or ambient air temperatureis between 40 and 50° F. (5 and 10° C.).

Two component approved casting adhesive may be preferable to fill thepavement hole to within approximately 1.81 in of the top of thepavement. RNTs should be preferably flush or a maximum of 0.25 in belowthe pavement surface and the RNT adhesive should ooze out from under theRNT from all sides filling all voids around the RNT and be level withthe pavement surface. An exemplary adhesive would be an epoxy resinadhesive. An exemplary method for installing and handling the adhesiveis found in AASHTO M 237-96 (2009), which is available from the AmericanAssociation of State Highway and Transportation Officials; 444 NorthCapitol Street N.W., Suite 249; Washington, D.C. 20001; the disclosureof this specification is herein incorporated by reference in itsentirety.

In an exemplary embodiment, each automobile contains an RFID antennawhich is typically placed on the undercarriage of an AMVG Systemcontrolled motor vehicle. The goal is to create the largest and mostpowerful magnetic field possible, thereby decreasing the amount of timerequired to fully charge the capacitor inside the RNTs. The shorter thecharge time, the faster a motor vehicle can operate using the AMVGSystem.

The layout of RNTs and placement of SLIZs is typically dependent on thesize of the RFID antenna and more specifically the magnetic field sizecreated by the RFID antenna. The size of the magnetic field can bedetermined by several factors. It can be engineered to a specific size,calculated based off a set of parameters, provided by the manufactureror measured. Also, the size of motor vehicles typically constraints thesize of the RFID antenna because it will be attached to the bottom ofthe chassis in a position such that there are no metallic componentsbetween the RFID antenna and the surface of the roadway.

In the embodiment shown in FIG. 1 a motor vehicle 160 shows attachedRFID antenna 50 with length L measured parallel to the flow of trafficand width W measured perpendicular to the flow of traffic. Generallyspeaking, and excluding motorcycles, the smallest motor vehiclecurrently manufactured for legal operation on U.S. public roadways has alength of 8 ft and width of 5 ft.

As an example, one design for an antenna would be as follows:

Magnetic Field Length: Preferably 7.5 ft

Magnetic Field Width: Preferably 4.5 ft

Magnetic Field Depth: Preferably based off the vehicle height above, theroad and magnetic field depth required to encompass all LF RFIDtransponders in the foregoing LF RFID antenna magnetic field perimetersize.

Wire Type: Preferably 12 AWG, Litz Wire; 24 AWG 12 Strands

Loops of Wire: Preferably 3

Wire Spacing: Preferably 0.75 in

Encasement Material: Preferably Polymer. RFID antenna wire shouldpreferably be covered by a minimum of 0.5 in and maximum of 1.5 in ofpolymer.

The RFID antenna should preferably be shielded by stainless steel,covering the encasement polymer to confine the size of themagnetic/signal transmission field created by the RFID antenna. Thiswill prevent more than one RNT from being charged at a time andeliminate interference from other AMVG System controlled motor vehiclestransmitting information.

An RFID reader is preferably used to initiate the magnetic field createdby the RFID antenna and decode the radio signal transmitted from theRNTs. An exemplary RFID reader creates a magnetic field for a definedperiod of time. The RFID reader may then stop producing the magneticfield and wait to receive a radio signal from a charged transponder.This reader cycle is preferably repeated continually while the reader ispowered and in operation. The time period during which the RFID antennacreates a magnetic field and awaits a response can be adjusted to allowfor the best operation of RFID technology for the application at hand.

The required charge time for an RFID transponder is directly related tothe amount of time needed for the reader to produce the magnetic field.The reader cycle time is decreased to the minimum magnetic fieldpulse/RFID transponder charge duration of 15 ms and the minimum radiosignal observation/RFID transponder signal transmission duration of 20ms. This cycle time of 35 ms maximizes the AMVG System's performance andis used in the simulation to validate the AMVG System's accuracy,thereby guaranteeing the speed limit of the roadway

FIG. 36 provides an electrical schematic of one embodiment for the motorvehicle components including the MVTCS. The MVTCS is the component thatconnects the AMVG System with the motor vehicle. This device receivesinformation from the RFID reader pertaining to the speed limit of theroadway. The RFID reader will preferably be programmed to store thesignal from multiple RNTs and to recognize duplicate information frommultiple RNTs as redundant information to ensure accurate informationtransmission. This information is then used by the device to monitor themotor vehicle's speed of travel, allowing the AMVG System toelectronically override the operator, if necessary, and control thespeed of travel. This link of communication between the RFID reader andthe motor vehicle will vary depending on the manufacturer and possiblyeven the motor vehicle style. This device may be developed with eachindividual motor vehicle manufacturer to enable communicationcapabilities with the MVTCS and Operator Warning System.

Visual and Audio Operator Warning Systems may be used to inform themotor vehicle operator of the AMVG Systems Roadway Network's interactionwith the motor vehicle. These warning systems also may vary depending onthe manufacturer and style of motor vehicle. These audio and visualsystems may consist of verbal and visual communication with the driver,identifying the speed limit of the roadway being traveled and itsrelation to current operation. This alone may help reduce a significantamount of speeding that occurs due to driver negligence with respect toposted speed limits of the roadway being traveled. The manner in whichthese warning systems operate can be determined by the vehiclemanufacturer and can be built as intricate as a motor vehicle isluxurious.

Additionally, motor vehicles can be programmed with information beforebecoming a working part of the system, allowing RFID transponders toevolve and control more than just the speed of motor vehicles. Forexample, RNTs could be used as warning devices or means for otherinformation transmission. Specifically, RNTs could be placed in roadwaysto identify Stop, Yield and Merge signs, as well as airports,restaurant, retail stores, gas station, parks and tourist attractions,among others.

Additionally, the high speed induction based charge transmissioninvented to power the RFID transponders (RNTs) can be used to powerother electrical devices embedded in the roadway. For example, roadwaytemperature sensors, ice and snow melting devices and otherinfrastructure sensing devices, among others.

In the embodiment shown in FIG. 37, a number of Dynamic RNTs 120 may beplaced in electrical communication with a computer network/internetconnection 110 which may be in communication with a computer 100. As themotor vehicle 160 travels over the roadway 170, the RFID antenna 140 mayreceive electrical signals from the Dynamic RNTs 120. The electricalsignals may be converted or otherwise interpreted by a processor 130 andcommunicated to the occupants of the automobile 160 through acommunication system 150. In some embodiments the communication system150 may be a flat panel display (LCD, OLED, etc.), audio communications,or both a flat panel display and audio communications.

This embodiment permits a user to update the information stored on theDynamic RNTs 120 through the computer 100 and computer network/internetconnection 110. This Information Communication Network System couldallow the user to provide information like construction detours, trafficdelays, Amber Alerts, breaking news, weather information and marketinginformation, among others.

Having shown and described preferred embodiments, those skilled in theart will realize that many variations and modifications may be made toaffect the described embodiments and still be within the scope of theclaimed invention. Additionally, many of the elements indicated abovemay be altered or replaced by different elements which will provide thesame result and fall within the spirit of the claimed invention. It isthe intention, therefore, to limit the invention only as indicated bythe scope of the claims.

I claim:
 1. A system for transmitting data to a motor vehicle travellingalong a roadway in a direction of travel, the motor vehicle having anantenna which produces a magnetic field having a length (L) in thedirection of travel and a width (W) perpendicular to the direction oftravel, the system comprising: a first plurality of low frequency RFIDtransponders placed within a roadway and positioned in a first row whichis perpendicular to the direction of travel, each transponder havingdata to be transferred to the motor vehicle; a second plurality of lowfrequency RFID transponders placed within a roadway and positioned in asecond row which is perpendicular to the direction of travel, eachtransponder having data to be transferred to the motor vehicle; wherethe second row is placed at distance (D) from the first row, where D ismeasured in a direction parallel to the direction of travel; and wherethe second row is offset from the first row.
 2. The system of claim 1wherein: the spacing between a pair of adjacent RFID transponders in thesame row is greater than W.
 3. The system of claim 1 wherein: the datais received at the motor vehicle at least twice when the motor vehiclepasses over one of the transponders while travelling less thanapproximately 30 miles per hour.
 4. The system of claim 1 wherein: D isgreater than L.
 5. The system of claim 1 wherein: the second row isoffset from the first row by distance (O), where O is measured in adirection that is perpendicular to the direction of travel, and O isbetween 40% and 60% of W.
 6. The system of claim 1 further comprising: athird plurality of low frequency RFID transponders placed within aroadway and positioned in a third row which is perpendicular to thedirection of travel, each transponder having data to be transferred tothe motor vehicle; a fourth plurality of low frequency RFID transpondersplaced within a roadway and positioned in a fourth row which isperpendicular to the direction of travel, each transponder having datato be transferred to the motor vehicle; where the third row follows thesecond row; where the fourth row follows the third row; where the thirdrow is offset from the second row; and where the fourth row is offsetfrom the third row.
 7. The system of claim 6 wherein: the data isreceived at the motor vehicle at least twice when the motor vehiclepasses over two of the transponders while travelling less thanapproximately 58 miles per hour.
 8. The system of claim 6 furthercomprising: a fifth plurality of low frequency RFID transponders placedwithin a roadway and positioned in a fifth row which is perpendicular tothe direction of travel, each transponder having data to be transferredto the motor vehicle; a sixth plurality of low frequency RFIDtransponders placed within a roadway and positioned in a sixth row whichis perpendicular to the direction of travel, each transponder havingdata to be transferred to the motor vehicle; where the fifth row followsthe fourth row; where the sixth row follows the fifth row; where thefifth row is offset from the fourth row; and where the sixth row isoffset from the fifth row.
 9. The system of claim 8 wherein: the data isreceived at the motor vehicle at least twice when the motor vehiclepasses over three of the transponders while travelling less thanapproximately 75 miles per hour.
 10. The system of claim 1 wherein: thedata is a maximum speed limit for the roadway.
 11. The system of claim 1wherein: the RFID transponders are active and placed in electricalcommunication with a network which is adapted to update the data storedon each RFID transponder.
 12. The system of claim 11 wherein: the datastored on the active RFID transponder is any one of the following: amberalerts, roadway conditions, and traffic information.
 13. The system ofclaim 1 wherein: the data is any one of the following: retail locationsin the vicinity of the transponder, tourist attractions in the vicinityof the transponder, and restaurant locations in the vicinity of thetransponder.
 14. A system for transmitting data to a motor vehicletravelling along a roadway in a direction of travel, the motor vehiclehaving an antenna which produces a magnetic field having a length (L) inthe direction of travel and a width (W) perpendicular to the directionof travel, the system comprising: an activation zone within the roadwaycomprising a plurality of low frequency RFID transponders placed withinthe roadway, each transponder having control data to be transferred tothe motor vehicle; a stretch of roadway following the activation zonewhere the motor vehicle operates based on the control data; and adeactivation zone following the stretch of roadway and comprising aplurality of low frequency RFID transponders placed within the roadway,each transponder having release data to be transferred to the motorvehicle, releasing control of the motor vehicle.
 15. The system of claim14 further comprising: a second deactivation zone preceding theactivation zone and comprising a plurality of low frequency RFIDtransponders placed within the roadway, each transponder having releasedata to be transferred to the motor vehicle.
 16. The system of claim 15wherein: the second deactivation zone is positioned adjacent to atraffic intersection.
 17. The system of claim 14 wherein: the RFIDtransponders are positioned in a series of rows where each row isperpendicular to the direction of travel, each row being offset from therow immediately preceding it by a distance (O) which is measured in adirection perpendicular to the direction of travel, and where each RFIDtransponder within a row is separated by at least W.
 18. A method forplacing low frequency RFID transponders in a roadway for datatransmission to a motor vehicle, the method comprising the steps of: (1)selecting a portion of the roadway for placing the RFID transponders;(2) determining the maximum speed attainable by the motor vehicle at theselected portion of roadway; (3) determining the dimensions of amagnetic field emanating from the motor vehicle, producing a length (L)in the direction of motor vehicle travel and a width (W) in a directionperpendicular to the vehicle travel; (4) determining how manytransponders the motor vehicle must pass over to read at least tworedundant sets of data, based on the result of step (2); (5) placing afirst row of transponders across the roadway, oriented in a directionperpendicular to the direction of travel, where each transponder withinthe row is spaced at least W from one another; (6) placing a second rowof transponders across the roadway, oriented in a directionperpendicular to the direction of travel, where each transponder withinthe row is spaced at least W from one another, and where the second rowis placed at least L from the first row, measured in the direction ofvehicle travel, and where the second row is offset from the first row ina direction perpendicular to the vehicle travel.
 19. The method of claim18 further comprising the steps of: (7) determining how many rows oftransponders are required, based on the result of the determining step(4); and (8) placing the remaining number of rows of transponders equalor greater to the result found in the determining step (7).